Cancelling an employee's leave

What does an employer do if an employee’s leave needs to be cancelled?
Scenario:
An employee applied for leave a month ago. He assured the employer that he had all his deadlines in check, and his work finished. The employer approves the employee’s leave application. The employee has paid for a week away with his family.
However, three days before the employee leaves, he is nowhere near reaching his deadline. What now?
Does the employer let him go away? After all, the employer has approved his leave. The employer is dependent on the employee to completing crucial information for customers and to retain those customers. Does the employer cancel his leave? This of course would not go down well with the employee as well as other staff. Telling the employee that he cannot go on leave anymore, would certainly cause issues.
How does an employer tell an employee that he cannot go on leave anymore?
If the employer and the employee agreed that he could go only if he had reached his deadline, then it is a case of, sorry, you cannot go. The employer would be within his rights to cancel the leave. However, it is suggested that the employer obtains a clear and reasonable agreement in writing with the employee that says he would not be allowed to go on leave if he has not met his deadlines. Only then can the employer say to the employee that he cannot go on leave. If the employee then still goes on leave, the employer can take action against him for being absent without permission.
But what happens if the employee has paid for his holiday? Is the employer responsible to reimburse the employee for the money he has already paid?
The answer to that question is….’No’. The employee agreed to meet his deadlines,and the fact that he did not  rests on his own shoulders. The employer is within its right to cancel the employee’s leave and the employee will forfeit any money he already paid. This is not the employer’s problem.
Having said that though, it needs to be repeated, the employer needs to get the employee’s agreement in writing!  This could also be an an informal e-mail. This will show the employee that the employer is serious. This unfortunately may seem like harsh reality. With today’s technology the employer could make an exception and let the employee go, if the employee agrees to work while on leave and to still meet his deadline.
The question then needs to be asked……What regard remains left for deadlines, performance and instructions if the employee has not fulfilled his end of the bargain? However, if there is no such agreement in place, the employer would have no right to cancel the employee’s leave once it has been granted. The employer’s only option then would be to negotiate a mutually satisfactory solution with the employee.